The objective of this project is to develop a package of brief, safe and reliable measures of exercise tolerance that, in total, is broadly applicable and highly discriminating in population studies of older persons. For the purposes of comparison across studies and assessment of change over time, the inter-relationship of measures of exercise tolerance to one another will be examined. Testing and evaluation is ongoing at the Baltimore Veterans Administration Medical Center. The following tests of exercise tolerance are being administered sequentially on two occasions 7 to 10 days apart to a volunteer sample of 50 men and women age 70-79 years, 35 of whom have no limitations in lower extremity function and 15 of whom have peripheral arterial disease: (1) self-report physical function; (2) timed measured walks (usual and fast pace 4-meter and 20-meter walks); (3) a 6-minute corridor walk; (4) seated step-test; and (5) treadmill walk-test. Heart rate at work, recovery heart rate, blood pressure, and oxygen consumption were measured. In addition, two questionnaires are being piloted. One is a further modification and refinement of Taylor's Leisure Time Physical Activity questionnaire and the other is a self-report measure of physical function that assesses ease of performance and level of fatigue as well as difficulty in performing higher order functional tasks. At the end of July, 28 of the 50 subjects have completed testing.